scholarly journals Opposing white matter microstructure abnormalities in 22q11.2 deletion and duplication carriers

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Johanna Seitz-Holland ◽  
Monica Lyons ◽  
Leila Kushan ◽  
Amy Lin ◽  
Julio E. Villalon-Reina ◽  
...  
Keyword(s):  
White Matter ◽  
Psychiatric Morbidity ◽  
Free Water ◽  
Water Model ◽  
22Q11.2 Deletion ◽  
Tissue Properties ◽  
Diffusion Weighted Images ◽  
Diffusion Weighted ◽  
Water Elimination ◽  
Number Variation

AbstractDeletions and duplications at the 22q11.2 locus are associated with significant neurodevelopmental and psychiatric morbidity. Previous diffusion-weighted magnetic resonance imaging (MRI) studies in 22q11.2 deletion carriers (22q-del) found nonspecific white matter (WM) abnormalities, characterized by higher fractional anisotropy. Here, utilizing novel imaging and processing methods that allow separation of signal contribution from different tissue properties, we investigate whether higher anisotropy is driven by (1) extracellular changes, (2) selective degeneration of secondary fibers, or (3) volumetric differences. We further, for the first time, investigate WM microstructure in 22q11.2 duplication carriers (22q-dup). Multi-shell diffusion-weighted images were acquired from 26 22q-del, 19 22q-dup, and 18 healthy individuals (HC). Images were fitted with the free-water model to estimate anisotropy following extracellular free-water elimination and with the novel BedpostX model to estimate fractional volumes of primary and secondary fiber populations. Outcome measures were compared between groups, with and without correction for WM and cerebrospinal fluid (CSF) volumes. In 22q-del, anisotropy following free-water elimination remained significantly higher compared with controls. BedpostX did not identify selective secondary fiber degeneration. Higher anisotropy diminished when correcting for the higher CSF and lower WM volumes. In contrast, 22q-dup had lower anisotropy and greater extracellular space than HC, not influenced by macrostructural volumes. Our findings demonstrate opposing effects of reciprocal 22q11.2 copy-number variation on WM, which may arise from distinct pathologies. In 22q-del, microstructural abnormalities may be secondary to enlarged CSF space and more densely packed WM. In 22q-dup, we see evidence for demyelination similar to what is commonly observed in neuropsychiatric disorders.

Diffusion Tensor Imaging and Fiber Tractography

2009 ◽  
pp. 229-246
Author(s):  
Evanthia E. Tripoliti ◽  
Dimitrios I. Fotiadis ◽  
Konstantia Veliou
Keyword(s):  
Diffusion Tensor Imaging ◽  
White Matter ◽  
Diffusion Tensor ◽  
Brain Regions ◽  
Cerebral White Matter ◽  
Tissue Microstructure ◽  
Diffusion Weighted Images ◽  
Fiber Tracts ◽  
Diffusion Weighted ◽  
Magnetic Resonance Imaging Mri

Diffusion Tensor Imaging (DTI) is a magnetic resonance imaging (MRI) modality which can significantly improve our understanding of the brain structures and neural connectivity. DTI measures are thought to be representative of brain tissue microstructure and are particularly useful for examining organized brain regions, such as white matter tract areas. DTI measures the water diffusion tensor using diffusion weighted pulse sequences which are sensitive to microscopic random water motion. The resulting diffusion weighted images (DWI) display and allow quantification of how water diffuses along axes or diffusion encoding directions. This can help to measure and quantify the tissue’s orientation and structure, making it an ideal tool for examining cerebral white matter and neural fiber tracts. In this chapter the authors discuss the theoretical aspects of DTI, the information that can be extracted from DTI data, and the use of the extracted information for the reconstruction of fiber tracts and the diagnosis of a disease. In addition, a review of known fiber tracking algorithms is presented.

scholarly journals Improving spatial normalization of brain diffusion MRI to measure longitudinal changes of tissue microstructure in the cortex and white matter

2019 ◽  
Author(s):  
Florencia Jacobacci ◽  
Jorge Jovicich ◽  
Gonzalo Lerner ◽  
Edson Amaro ◽  
Jorge L. Armony ◽  
...  
Keyword(s):  
White Matter ◽  
Gray Matter ◽  
Repeated Measures ◽  
Statistical Tests ◽  
Mean Diffusivity ◽  
Prospective Longitudinal Study ◽  
Longitudinal Changes ◽  
Diffusion Weighted Images ◽  
Diffusion Weighted ◽  
Prospective Longitudinal

ABSTRACTBackgroundFractional anisotropy (FA) and mean diffusivity (MD) are frequently used to evaluate longitudinal changes in white matter microstructure. Recently, there has been a growing interest in identifying experience-dependent plasticity in gray matter using MD. Improving registration has thus become a major goal to enhance the detection of subtle longitudinal changes in cortical microstructure.PurposeTo optimize normalization to improve registration in gray matter and reduce variability associated with multi-session registrations.Study TypeProspective longitudinal studySubjectsTwenty-one healthy subjects (18-31 years old) underwent 9 magnetic resonance imaging (MRI) scanning sessions each.Field Strength/Sequence3.0T, diffusion-weighted multiband-accelerated sequence, MP2RAGE sequence.AssessmentDiffusion-weighted images were registered to standard space using different pipelines that varied in the features used for normalization, namely the non-linear registration algorithm (FSL vs ANTs), the registration target (FA-based vs T1-based templates), and the use of intermediate individual (FA-based or T1-based) targets. We compared the across-session test-retest reproducibility error from these normalization approaches for FA and MD in white and gray matters.Statistical TestsReproducibility errors were compared using a repeated-measures analysis of variance with pipeline as within-subject factor.ResultsThe registration of FA data to the FMRIB58 FA atlas using ANTs yielded lower reproducibility errors in white matter (p<0.0001) with respect to FSL. Moreover, using the MNI152 T1 template as the target of registration resulted in lower reproducibility errors for MD (p<0.0001), whereas the FMRIB58 FA template performed better for FA (p<0.0001). Finally, the use of an intermediate individual template improved reproducibility when registration of the FA images to the MNI152-T1 was carried out within modality (FA-FA) (p<0.05), but not via a T1-based individual template.Data ConclusionA normalization approach using ANTs to register FA images to the MNI152 T1 template via an individual FA template minimized test-retest reproducibility errors both for gray and white matter.

scholarly journals Correction strategy for diffusion-weighted images corrupted with motion: application to the DTI evaluation of infants' white matter

2014 ◽  
Vol 32 (8) ◽  
pp. 981-992 ◽  
Author(s):  
Jessica Dubois ◽  
Sofya Kulikova ◽  
Lucie Hertz-Pannier ◽  
Jean-François Mangin ◽  
Ghislaine Dehaene-Lambertz ◽  
...  
Keyword(s):  
White Matter ◽  
Diffusion Weighted Images ◽  
Diffusion Weighted

scholarly journals M155. RECIPROCAL CHANGES IN WHITE MATTER MICROSTRUCTURE IN 22Q11.2 DELETION AND DUPLICATION SYNDROME

2020 ◽  
Vol 46 (Supplement_1) ◽  
pp. S194-S195
Author(s):  
Johanna Seitz ◽  
Monica Lyons ◽  
Leila Kushan ◽  
Kang Ik Kevin Cho ◽  
Tashrif Billah ◽  
...  
Keyword(s):  
White Matter ◽  
Symptom Score ◽  
Negative Symptom ◽  
Free Water ◽  
22Q11.2 Deletion Syndrome ◽  
Deletion Syndrome ◽  
Psychotic Symptoms ◽  
22Q11.2 Deletion ◽  
White Matter Microstructure ◽  
Human Connectome Project

Abstract Background The 22q11.2 deletion syndrome is a neurogenetic disorder that is associated with both physical anomalies and neurocognitive impairments. Deletion carriers have a greatly elevated risk of developing schizophrenia (SCZ); as such, it offers a compelling ‘high-penetrance’ model to explore the neuropathology of SCZ risk. Indeed, widespread structural alterations of both gray and white matter have been reported for 22q11.2 deletion carriers. Interestingly, there are also cases of duplications at the same gene locus. While less is known about the phenotype associated with 22q11.2 duplication, carriers also present physical and neurodevelopmental abnormalities, although they may have reduced risk of developing SCZ compared to the general population. The only study to date which looked at brain structure in duplication carriers found reciprocal effects of 22q11.2 deletion and duplication on cortical thickness and surface measurements. In the present study, we apply diffusion magnetic resonance imaging (MRI) to examine the white matter microstructure in both 22q11.2 deletion and duplication carriers. Methods Multi-shell diffusion-weighted images were acquired on a 3 Tesla MRI scanner from 13 healthy control individuals (HC), 25 deletion carriers, and 18 22q11.2 duplication carriers. Images were preprocessed utilizing the Human Connectome Project (HCP) Minimal Preprocessing Pipeline v4.0.0. Free Water imaging was applied, which differentiates the diffusion signal into a free-water compartment and a tissue compartment. The output parameters are the free-water fractional volume (FW) and a free-water corrected diffusion tensor from which fractional anisotropy of the tissue (FAT) is calculated. We compared FAT and FW maps between 1) HC and 22q11.2 deletion carriers and 2) HC and 22q11.2 duplication carriers using Tract-Based Spatial Statistics (TBSS) and voxel-wise, non-parametric statistics (5000 permutations, threshold-free cluster enhancement, corrected for age and sex). Lastly, white matter clusters that displayed significant differences between 22q11.2 deletion or duplication and HC were extracted. We averaged FAT and FW values over these significant clusters for each individual and correlated with the scores of the Structured Interview for Prodromal Syndromes (SIPS). Results 22q11.2 deletion carriers showed significant (p&lt;0.05) FW reductions (72% of white matter skeleton) and FAT increase (8%) when compared to HC. In contrast, 22q11.2 duplication carriers displayed the opposite effect, with significant (p&lt;0.05) widespread FW increase (51%) and FAT decrease (50%) when compared to HC. Both 22q11.2 deletion and duplication carriers scored higher on the SIPS than HC, with negative symptom score differences being the most pronounced (mean for HC= 1.36, mean for 22q11.2 duplication = 7.0, mean for 22q11.2 deletion =9.96, F=6.68, df=2, p&lt;.003). FAT and FW were not associated with SIPS scores in 22q11.2 deletion syndrome. However, FAT was negatively correlated with the negative symptom score in 22q11.2 duplication carriers (Spearman rho=-.61, p&lt;.009). Discussion We observed opposing effects of gene-dosage on FAT and FW. While we did not see an association between WM measurements and psychotic symptoms in 22q11.2 deletion, there was an association of WM structure with negative symptoms in 22q11.2 duplication carriers. These findings highlight the importance of studying the influence of reciprocal chromosomal imbalance on white matter architecture. Ongoing longitudinal studies may help advance understanding of the role of microstructural white matter abnormalities in the emergence of neuropsychiatric symptoms.

scholarly journals [Re] Optimization of a free water elimination two-compartment model for diffusion tensor imaging

2017 ◽  
Author(s):  
Rafael Neto Henriques ◽  
Ariel Rokem ◽  
Eleftherios Garyfallidis ◽  
Samuel St-Jean ◽  
Eric Thomas Peterson ◽  
...  
Keyword(s):  
Diffusion Tensor Imaging ◽  
Diffusion Mri ◽  
Diffusion Tensor ◽  
Free Water ◽  
Compartment Model ◽  
B Values ◽  
Brain White Matter ◽  
Diffusion Weighted ◽  
Two Compartment Model ◽  
Water Elimination

Typical diffusion-weighted imaging (DWI) is susceptible to partial volume effects: different types of tissue that reside in the same voxel are inextricably mixed. For instance, in regions near the cerebral ventricles or parenchyma, fractional anisotropy (FA) from diffusion tensor imaging (DTI) may be underestimated, due to partial volumes of cerebral spinal fluid (CSF). Free-water can be suppressed by adding parameters to diffusion MRI models. For example, the DTI model can be extended to separately take into account the contributions of tissue and CSF, by representing the tissue compartment with an anisotropic diffusion tensor and the CSF compartment as an isotropic free water diffusion coefficient. Recently, two procedures were proposed to fit this two-compartment model to diffusion-weighted data acquired for at least two different non-zero diffusion MRI b-values. In this work, the first open-source reference implementation of these procedures is provided. In addition to presenting some methodological improvements that increase model fitting robustness, the free water DTI procedures are re-evaluated using Monte-Carlo multicompartmental simulations. Analogous to previous studies, our results show that the free water elimination DTI model is able to remove confounding effects of fast diffusion for typical FA values of brain white matter. In addition, this study confirms that for a fixed scanning time the fwDTI fitting procedures have better performance when data is acquired for diffusion gradient direction evenly distributed along two b-values of 500 and 1500 s/mm2.

Fludarabine-Associated Neurotoxicity After Hematopoietic Cell Transplantation (HCT): Clinical and Radiographic Features Predict Outcome.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 2270-2270
Author(s):  
Amer Beitinjaneh ◽  
Alexander McKinney ◽  
Qing Cao ◽  
Daniel J. Weisdorf
Keyword(s):  
White Matter ◽  
Cognitive Dysfunction ◽  
Hematopoietic Cell Transplantation ◽  
Conflicts Of Interest ◽  
Cns Infection ◽  
Periventricular White Matter ◽  
Prognostic Information ◽  
Diffusion Weighted Images ◽  
Toxic Leukoencephalopathy ◽  
Diffusion Weighted

Abstract Abstract 2270 Poster Board II-247 Central nervous system (CNS) toxicity after HCT is an uncommon, but serious cause of transplant related mortality. Recently, toxic leukoencephalopathy is better defined using advanced MRI techniques. We reviewed all the medical records of HCT recipients (2000-2007) who received Flu-containing conditioning regimens in our institution and developed sever central nervous toxicity. We asked a specialized neuroradiologist to review their brain imagines blindly from patients' outcomes. From our database review, cases were excluded if neurologic symptoms were related to peripheral neuropathy, CNS infection, intracranial bleeding, stroke, CNS malignancy, sedative medication effect, or metabolic disturbance. We were able to identify 39 cases of sever leukoencephalopathy out of total1596 transplants and we described 3 distinct Flu-associated clinical syndromes with unique clinical and radiographic characteristics. Posterior reversible encephalopathy syndrome (PRES, n=17, 1.1%) presented with seizures, persistent headache, or visual changes along with varying compromise in mental status. Acute Toxic Leukoencephalopathy, (ATL, n=11, 0.7%) resulted mainly in cognitive dysfunction, decreased levels of consciousness, and some vision changes. A third distinct Leukoencephalopathy syndrome (LS, n=11, 0.7%) presented similarly to ATL but with less specific and chronic-appearing deep white matter changes on MRI. PRES favors the cortex/subcortical white matter (SCWM) in the early phases and ATL/LS favor the deep periventricular white matter (PVWM) in the early stages, these two entities can usually be distinguished from each other utilizing the combination of fluid-attenuated inversion recovery (FLAIR) and diffusion-weighted images (DWI) MRI techniques (Typically diffusion is reduced in ATL and normal in PRES). Other associated features included: younger age in PRES (median 20 years vs. 55 in ATL and 42 in LS). ATL and LS can be reversible, but to a lesser degree than PRES. PRES developed later (median 77 days post HCT) compared to 30 and 31 days for ATL and LS. Patients who developed ATL had shorter overall survivals than patients with PRES and LS patients (Median overall survival was 6.9 month for PRES compared to 2 months in ATL). ATL/LS compared to PRES were more likely to present with cognitive dysfunction than seizure (refer to table). Flu-associated ATL/LS may be more common in older patients, those with renal dysfunction, prior CNS radiation or chemotherapy, and in patients received higher dose of Flu compared to PRES. Our review suggests Brian MRI with Diffusion-weighted imaging (DWI) can add considerable diagnostic and prognostic information. Prospective Flu pharmacokinetic and pharmacogenetic studies may be needed to determine the most appropriate Flu dosing to avoid neurotoxicity. Table: Brief summary of patients' characteristics and clinical features. Different Groups Total PRES ATL LS Number 39 17 11 11 Median Age (range) 43 (3-69) 20 55 42 Total conditioning FLU (mg/m2) 200 144 200 200 Baseline Cr CL (mg/min/1.73 m2) 92 100.6 81 85.3 Previous     Flud 3 0 3 0     CNS Therapy 13 2 6 5     HCT 9 2 5 2 Presenting Symptom     Seizure 8 (21%) 7 (41%) 0 1     Confusion /cognitive 12 (30%) 2(12%) 5 (46%) 5 (46%) Median survival (days) 169 208 66 204 Death Related 13 2 7 4 Disclosures: No relevant conflicts of interest to declare.

scholarly journals Microstructural white matter alterations in preclinical Alzheimer’s disease detected using free water elimination diffusion tensor imaging

PLoS ONE ◽  
2017 ◽  
Vol 12 (3) ◽  
pp. e0173982 ◽  
Author(s):  
Andrew R. Hoy ◽  
Martina Ly ◽  
Cynthia M. Carlsson ◽  
Ozioma C. Okonkwo ◽  
Henrik Zetterberg ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Diffusion Tensor Imaging ◽  
White Matter ◽  
Diffusion Tensor ◽  
Free Water ◽  
Preclinical Alzheimer’S Disease ◽  
Water Elimination

scholarly journals Free water: A marker of age-related modifications of the cingulum white matter and its association with cognitive decline

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0242696
Author(s):  
Manon Edde ◽  
Guillaume Theaud ◽  
François Rheault ◽  
Bixente Dilharreguy ◽  
Catherine Helmer ◽  
...  
Keyword(s):  
White Matter ◽  
Cognitive Decline ◽  
Verbal Fluency ◽  
White Matter Hyperintensities ◽  
Free Water ◽  
Partial Volume ◽  
Cingulum Bundle ◽  
Partial Volume Effects ◽  
Age Related ◽  
Water Elimination

Diffusion MRI is extensively used to investigate changes in white matter microstructure. However, diffusion measures within white matter tissue can be affected by partial volume effects due to cerebrospinal fluid and white matter hyperintensities, especially in the aging brain. In previous aging studies, the cingulum bundle that plays a central role in the architecture of the brain networks supporting cognitive functions has been associated with cognitive deficits. However, most of these studies did not consider the partial volume effects on diffusion measures. The aim of this study was to evaluate the effect of free water elimination on diffusion measures of the cingulum in a group of 68 healthy elderly individuals. We first determined the effect of free water elimination on conventional DTI measures and then examined the effect of free water elimination on verbal fluency performance over 12 years. The cingulum bundle was reconstructed with a tractography pipeline including a white matter hyperintensities mask to limit the negative impact of hyperintensities on fiber tracking algorithms. We observed that free water elimination increased the ability of conventional DTI measures to detect associations between tissue diffusion measures of the cingulum and changes in verbal fluency in older individuals. Moreover, free water content and mean diffusivity measured along the cingulum were independently associated with changes in verbal fluency. This suggests that both tissue modifications and an increase in interstitial isotropic water would contribute to cognitive decline. These observations reinforce the importance of using free water elimination when studying brain aging and indicate that free water itself could be a relevant marker for age-related cingulum white matter modifications and cognitive decline.

scholarly journals Cerebral White Matter Lesions on Diffusion-Weighted Images and Delayed Neurological Sequelae after Carbon Monoxide Poisoning: A Prospective Observational Study

Diagnostics ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 698
Author(s):  
Sangun Nah ◽  
Sungwoo Choi ◽  
Han Bit Kim ◽  
Jungbin Lee ◽  
Sun-Uk Lee ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
White Matter ◽  
Carbon Monoxide Poisoning ◽  
Subsequent Development ◽  
Brain Lesions ◽  
University Hospital ◽  
Co Poisoning ◽  
Neurological Sequelae ◽  
Diffusion Weighted Images ◽  
Diffusion Weighted

Introduction: Carbon monoxide (CO) poisoning can result in delayed neurological sequelae (DNS). Factors predicting DNS are still controversial. This study aims to determine whether acute brain lesions observed using diffusion-weighted magnetic resonance imaging (MRI) following acute CO poisoning are related to the subsequent development of DNS. Methods: This prospective study was conducted on patients with CO poisoning treated at a university hospital in Bucheon, Korea. From August 2016 to July 2019, a total of 283 patients visited the hospital because of CO poisoning. Exclusion criteria included age under 18 years, refusing hyperbaric oxygen therapy, refusing MRI, being discharged against medical advice, being lost to follow-up, having persistent neurological symptoms at discharge, and being transferred from another hospital 24 h after exposure. Results: Of the 154 patients included in the final study, acute brain lesions on MRI (ABLM) were observed in 49 patients (31.8%) and DNS occurred in 30 patients (19.5%). In a logistic regression analysis, lower Glasgow coma scale score and higher exposure time were associated with DNS, and the presence of ABLM in white matter was significantly associated with DNS (OR 6.741; 95% CI, 1.843–24.660; p = 0.004). Conclusion: The presence of ABLM in white matter was significantly related to the occurrence of DNS. Early prediction of the risk of developing DNS through MRI may be helpful in treating patients with CO poisoning.

Sign in / Sign up

Export Citation Format

Share Document